AGL Resources has begun the permitting process for the controversial expansion of its natural gas storage facility in salt domes under Lake Peigneur in Iberia Parish.

The company filed a notice last month of its plans to seek a permit from the state Department of Natural Resources to build two more massive underground storage caverns under the lake more thandoubling gas storage capacity.

The actual permit could be filed as early as this month, setting in motion a series of governmental reviews of the company's plans and a public comment period.